Light sensing device having a lens

ABSTRACT

Light sensing devices are described that have a lens to focus light. In one or more implementations, the light sensing devices include a substrate having a photodetector formed thereon. The photodetector is capable of detecting light and providing a signal in response thereto. The devices also include a display screen that allows light to at least substantially pass through the display screen. An optical baffle extends above a surface of the substrate to display screen and is configured to at least substantially prevent transmission of optical crosstalk to the photodetector. The devices also include a lens disposed proximate to the display screen. The lens is configured to focus light incident upon the lens and to pass the focused light to the photodetector.

CROSS-REFERENCE TO RELATED APPLICATIONS

The present application claims the benefit under 35 U.S.C. §119(e) ofU.S. Provisional Application Ser. No. 61/564,341, entitled LIGHT SENSINGDEVICE HAVING A LENS, filed on Nov. 29, 2011. U.S. ProvisionalApplication Ser. No. 61/564,341 is herein incorporated by reference intheir entireties.

BACKGROUND

Electronic devices, such as smart phones, tablet devices, laptop anddesk top computers, digital media players, and so forth, increasinglyemploy light sensors to control the manipulation of a variety offunctions provided by the device. For example, light sensors arecommonly used by electronic devices to detect ambient lightingconditions in order to control the brightness of the device's displayscreen and the keyboard. Typical light sensors employ photodetectorssuch as photodiodes, phototransistors, or the like, which convertreceived light into an electrical signal (e.g., a current or voltage,analog or digital).

Light sensing devices are commonly used in gesture or proximity sensingdevices. Gesture sensing devices enable the detection of physicalmovement largely parallel to the display surface (e.g., “gestures”)without the user actually touching the device within which the gesturesensing device resides. Proximity sensing devices enable the detectionof physical movement that is largely perpendicular to the displaysurface (e.g., proximate to the display surface). The detected movementscan be subsequently used as input command for the device. Inimplementations, the electronic device is programmed to recognizedistinct non-contact hand motions, such as left-to-right, right-to-left,up-to-down, down-to-up, in-to-out, out-to-in, and so forth. Gesture andproximity sensing devices have found popular use in handheld electronicdevices such as tablet computing devices and smart phones, as well asother portable electronic devices such as laptop computers, video gameconsoles, and so forth.

SUMMARY

Light sensing devices are described that have a lens to focus light. Inone or more implementations, the light sensing devices include asubstrate having a photodetector formed thereon. The photodetector iscapable of detecting light and providing a signal in response thereto.The devices also include a display screen that allows light to at leastsubstantially pass through the display screen. An optical baffle extendsabove a surface of the substrate to display screen and is configured toat least substantially prevent transmission of optical crosstalk to thephotodetector. The devices also include a lens disposed proximate to thedisplay screen. The lens is configured to focus light incident upon thelens and to pass the focused light to the photodetector.

This Summary is provided to introduce a selection of concepts in asimplified form that are further described below in the DetailedDescription. This Summary is not intended to identify key features oressential features of the claimed subject matter, nor is it intended tobe used as an aid in determining the scope of the claimed subjectmatter.

DRAWINGS

The detailed description is described with reference to the accompanyingfigures. The use of the same reference numbers in different instances inthe description and the figures may indicate similar or identical items.

FIG. 1 is a diagrammatic partial cross-sectional side view illustratinga light sensing device having an illumination source, a photodetector,an optical baffle, a display screen, and a lens disposed proximate tothe display screen in accordance with an example implementation of thepresent disclosure, where the lens is disposed within a casing andpositioned over the photodetector.

FIG. 2 is a diagrammatic partial cross-sectional view illustrating alight sensing device in accordance with another example implementationof the present disclosure, where the lens is disposed over an interiorsurface of the display screen and positioned over the photodetector.

FIG. 3 is a diagrammatic partial cross-sectional view illustrating alight sensing device in accordance with another example implementationof the present disclosure, where the light sensing device includes alens support structure that is configured to hold the lens in place overthe photodetector.

FIG. 4 is a diagrammatic partial cross-sectional view illustrating alight sensing device in accordance with another example implementationof the present disclosure, where the lens is disposed over an exteriorsurface of the display screen.

DETAILED DESCRIPTION

Overview

Gesture or proximity sensing devices typically include light sensingdevices to allow for detection of physical movement in proximity to thedevices. These light sensing devices are configured to detect light thatis generated from an illumination source and reflected from an object,such as a finger or a hand, in proximity to the sensor. To collect morelight to enhance the signal, light sensing devices may include a lensformed directly on top of a photodetector. However, for reason of costand manufacturability, the acceptable lens dimension may be limited bythe photodetector, which may require a high power (short focal length)lens, which increase the cost and reduce the signal amplitude of thedetector. As the amplitude of the detector is reduced, the illuminationsource may require a greater amount of current to generate light signalsufficient above noise to be detected by the photodetector.Correspondingly, the greater amount of current required by theillumination source drains the battery power source of the light sensingdevice.

Accordingly, light sensing devices are described that have a lensdisposed (e.g., formed, positioned, etc.) proximate to a display screenof the devices. By positioning the lens proximate to the display screen,the lens dimensions may not be limited by the photodetector. Forexample, a lower power (longer focal length) lens can be used. Thus, thebattery power requirements of the illumination source may also bereduced. In one or more implementations, the light sensing devicesinclude a substrate having a photodetector formed thereon. The lightsensing devices may, in some implementations, further include anillumination source that is configured to generate light. In a specificimplementation, the light sensing devices may include a singleillumination source. The photodetector is capable of detecting lightemitted from the illumination source and providing a signal in responsethereto. In another specific implementation, the photodetector may beconfigured as a quad segmented photodetector. The light sensing devicesalso include a display screen that allows illuminating light andreflected light to at least substantially pass through the displayscreen. An optical baffle is disposed between the illumination sourceand the photodetector to at least substantially prevent opticalcrosstalk between the illumination source and the photodetector. Thesensors also include a lens disposed proximate to the display screen.The lens is configured to focus light incident upon the lens and to passthe focused light to the photodetector.

In the following discussion, example implementations of light sensingdevices having a lens are described.

Example Implementations

FIGS. 1 through 4 illustrate light sensing device 100 in accordance withan example implementation of the present disclosure. As shown, the lightsensing device 100 includes a substrate 102 for providing support to oneor more electronic components. The substrate 102 is also configured toprovide connective functionality between the various electroniccomponents of the light sensing device 100. For example, the substratemay comprise a printed circuit board (PCB), a flexible circuit harness,or the like. Thus, the substrate 102 may provide support to multipleelectronic components, such as digital integrated circuits, analogintegrated circuits, or combinations thereof.

The substrate 102 of each light sensing device 100 is illustrated ashaving a surface 104. A photodetector 106 (e.g., a light sensor) isdisposed over the surface 104 of the substrate 102. The photodetector106 is comprised of a semiconductor substrate 108 that furnishes a basematerial utilized to form one or more electronic devices through variousfabrication techniques such as photolithography, ion implantation,deposition, etching, and so forth. The semiconductor substrate 108 maycomprise n-type silicon (e.g., a silicon doped with a group carrierelement, such as a group V element [e.g., phosphorus, arsenic, antimony,etc.], to furnish n-type charge carrier elements to the silicon) orp-type silicon (e.g., silicon doped with a group carrier element, suchas a group IIIA element [e.g., boron, etc.], to furnish p-type chargecarrier elements to the silicon, or other group elements to furnishp-type charge carrier elements). While a silicon substrate is described,it is understood that other types of substrates may be utilized withoutdeparting from the scope of this disclosure. For example, thesemiconductor substrate 108 may be comprised of silicon-germanium,gallium-arsenide, or the like.

The photodetector 106 may be configured in a variety of ways. Forexample, the photodetector 106 may comprise a photo sensor diode, aphototransistor, or the like. In an implementation, the photodetector106 is capable of detecting light and providing a signal in responsethereto. The photodetector 106 may provide a signal by converting lightinto current or voltage based upon the intensity of the detected light.Thus, once a photodetector is exposed to light, multiple free electronsmay be generated to create current. The photodetector 106 is configuredto detect light in both the visible light spectrum and the near infraredlight spectrum. As used herein, the term “light” is contemplated toencompass electromagnetic radiation occurring in the visible lightspectrum and the near infrared light spectrum. The visible lightspectrum (visible light) includes electromagnetic radiation occurring inthe range of wavelengths from approximately three hundred and ninety(390) nanometers to approximately seven hundred and fifty (750)nanometers. Similarly, the near infrared light spectrum (infrared light)includes electromagnetic radiation that ranges in wavelength fromapproximately seven hundred (700) nanometers to approximately three (3)microns. In one or more implementations, complimentarymetal-oxide-semiconductor (CMOS) fabrication techniques may be utilizedto form the photodetector 106.

As described above, the photodetector 106 is configured to detect alight and provide a signal in response thereto. In one or moreimplementations, the light sensing device 100 may be configured for useas or in a gesture or proximity sensing device (e.g., a device thatdetects when an object, such as a hand or a finger, is brought inproximity to the device 100). In such implementations, the photodetector106 detects light reflected from an object (e.g., hand or finger) whenthe object is proximate to the device 100.

The light sensing device 100 also includes an illumination source 110that is configured to generate light (e.g., near infrared light orvisible light). Thus, the light detected (e.g., the light that isreflected from an object proximate to the light sensing device 100) bythe photodetector 106 is the light generated and emitted from theillumination source 110. Thus, the photodetector 106 is configured todetect light in a specific wavelength or wavelengths of light. Forexample, the illumination source 110 may generate a light occurring in afirst spectrum of wavelengths. The photodetector 106 may configured todetect light only occurring within the first spectrum of wavelengths. Inone or more implementations, the illumination source 110 may be a singlelight emitting diode, a single laser diode, or another type of lightsource.

In an implementation, the photodetector 106 may be configured as asegmented photodetector 106. The segmented photodetector 106 can beeither a single detector functionally partitioned into multiple segmentsor an array of individual photodetectors. For example, a quad segmentedphotodetector is functionally equivalent to four (4) individualphotodetectors arranged in a quad layout.

The device 100 includes a display screen 112 that is configured to atleast substantially allow light emitted by the illumination source 110to pass through the display screen 112. The display screen 112 is alsoconfigured to at substantially allow light reflected from an object topass through the display screen 112 to the photodetector 106. Forexample, an object (e.g., a hand, a finger, etc.) proximate to thedisplay screen 112 may reflect light generated from the illuminationsource 110 back through the display screen 112 to the photodetector 106.The photodetector 106 detects the reflected light and provides a signalin response thereto. The display screen 112 includes a first surface114, which is proximal to the photodetector 106, and a second surface116, which is distal to the photodetector 106. In an implementation, thedisplay screen 112 may be manufactured from a scratch-resistancematerial, or the like.

As shown in FIGS. 1 through 4, the photodetector 106 and theillumination source 110 are separated by an optical baffle 118 extendingbetween the substrate 102 and the display screen 112. The optical baffle118 is configured to prevent optical crosstalk to occur between theillumination source 110 and the photodetector 106. For example, theoptical baffle 118 may at least substantially prevent reflected lightemitted from the illumination source 110 to reach the photodetector 106.In an embodiment, the optical baffle 118 may be a casted metallic ridge,a molded plastic patrician, a preformed rubber gasket, or the like.

The device 100 includes a lens 120 to focus and transmit light incidentthereon (e.g., light incident upon the lens 120 from multiple angles).For example, the lens 120 may be configured to collimate the lightincident on the lens 120. In one or more implementations, the lens 120may be a glass lens, a plastic lens, a spherical lens, an asphericallens, a Fresnel-type lens, or the like.

In an implementation, as shown in FIG. 1, the lens 120 may be disposedwithin a casing 122. The casing 122 may be coupled to the display screen112 and configured to provide support to the display screen 112 andprotection to the components (e.g., substrate 102, photodetector 106,illumination source 110, etc.) of the light sensing device 100. Asshown, the lens 120 is enclosed within the casing 122 such that the lens120 is disposed over the photodetector 106. The casing 122 may beconfigured in a variety of ways. For example, the casing may be amolding composition, a plastic composition, or the like.

In another implementation, as shown in FIG. 2, the lens 120 is disposedover the first surface 114 of the display screen 112. Thus, lightreflected from an object proximate to the device 100 passes through thedisplay screen 112 (the portion of the display screen 112 having thelens 120 disposed thereon) and is then focused by the lens 120, which isthen passed to the photodetector 106. The lens 120 may be bonded to thefirst surface 114 with a suitable adhesive material, such as opticalcement, or the like.

In yet another implementation, as shown in FIG. 3, the lens 120 isdisposed within a lens support structure 122 that includes a firstsupport potion 124 and a second support portion 126. The supportportions 124, 126 are configured to hold the lens 120 over thephotodetector 106. The first support portion 124 of the lens supportstructure 122 also comprises the optical baffle 118. Thus, the firstsupport portion 124 functions to at least substantially prevent opticalcrosstalk between the illumination source 110 and the photodetector 106and functions to at least partially hold the lens 120 in position. Asshown, the support portions 124, 126 are coupled to the surface 104 ofthe substrate 102.

In yet another implementation, as shown in FIG. 4, the lens 120 isdisposed over the second surface 116 of the display screen 112. Inaddition to focusing and passing the focused light to the photodetector106, the lens 120 may also serve to allow users to locate a particularportion of the device 100 that receives gesture motions and subsequentlyun-lock the devices with certain specific hand or finger gestureswithout physically touching the display screen. Thus, a user may presenta specific finger or hand gesture proximate to the lens 120. Thephotodetector 106 may detect light reflected from the specific gestureand provide an un-lock signal in response to the detected light (e.g.,light reflected in a specific pattern based upon the specific gesture).The un-lock signal may be utilized to unlock an electronic device (e.g.,a tablet device, a smart phone, etc.) that the device 100 isincorporated within. Additionally, the user may be able to feel or seewhere the lens 120 is positioned since the lens 120 extends beyond aplane defined by the first surface 114 of the display screen 112. Thelens 120 may also display screen 112 against an abrasive surface, suchas a table or desk surface. (e.g., the screen 112 is oriented towards asurface).

Conclusion

Although the subject matter has been described in language specific tostructural features and/or process operations, it is to be understoodthat the subject matter defined in the appended claims is notnecessarily limited to the specific features or acts described above.Rather, the specific features and acts described above are disclosed asexample forms of implementing the claims.

What is claimed is:
 1. A light sensing device comprising: a substratehaving a surface; a photodetector disposed over the surface of thesubstrate, the photodetector configured to detect light and to provide asignal in response thereto; an optical baffle extending from the surfaceto a display screen, the optical baffle configured to at leastsubstantially prevent transmission of optical crosstalk to thephotodetector; and a lens configured to be disposed proximate to thedisplay screen, the lens configured to focus light incident upon thelens and to pass the focused light to the photodetector.
 2. The lightsensing device as recited in claim 1, wherein the lens is disposed overthe second surface of the display screen, the lens extending beyond aplane defined by the second surface of the display screen.
 3. The lightsensing device as recited in claim 1, further comprising a lens supportstructure disposed over the surface of the substrate, the lens supportstructure including a first support potion and a second support portion,the first and the second support portions configured to hold the lensover the photodetector.
 4. The light sensing device as recited in claim1, further comprising a casing at least partially disposed over thesubstrate and the photodetector, wherein the lens is disposed within thecasing over the photodetector.
 5. The light sensing device as recited inclaim 1, wherein the lens is disposed over the first surface of thedisplay screen.
 6. The light sensing device as recited in claim 1,wherein the display screen is a scratch-resistance glass material. 7.The light sensing device as recited in claim 1, wherein thephotodetector comprises a quad segmented photodetector.
 8. The lightsensing device as recited in claim 1, wherein the photodetector isconfigured to generate an un-lock signal.
 9. A light sensing devicecomprising: a substrate having a surface; an illumination sourcedisposed over the surface of the substrate, the illumination sourceconfigured to generate light; a photodetector disposed over the surfaceof the substrate, the photodetector configured to detect light emittedfrom the illumination source and to provide a signal in responsethereto; an optical baffle disposed between the illumination source andthe photodetector, the optical baffle configured to at leastsubstantially prevent optical crosstalk between the illumination sourceand the photodetector; and a lens configured to be disposed proximate toa display screen, the lens configured to focus light incident upon thelens and to pass the focused light to the photodetector.
 10. The lightsensing device as recited in claim 9, wherein the lens is disposed overthe second surface of the display screen, the lens extending beyond aplane defined by the second surface of the display screen.
 11. The lightsensing device as recited in claim 9, further comprising a lens supportstructure disposed over the surface of the substrate, the lens supportstructure including a first support potion and a second support portion,the first and the second support portions configured to hold the lensover the photodetector.
 12. The light sensing device as recited in claim9, further comprising a casing at least partially disposed over thesubstrate and the photodetector, wherein the lens is disposed within thecasing over the photodetector.
 13. The light sensing device as recitedin claim 9, wherein the lens is disposed over the first surface of thedisplay screen.
 14. The light sensing device as recited in claim 9,wherein the display screen is a scratch-resistance glass material. 15.The light sensing device as recited in claim 9, wherein thephotodetector comprises a quad segmented photodetector.
 16. The lightsensing device as recited in claim 9, wherein the photodetector isconfigured to generate an un-lock signal.
 17. A light sensing devicecomprising: a substrate having a surface; an illumination sourcedisposed over the surface of the substrate, the illumination sourceconfigured to generate light; a photodetector disposed over the surfaceof the substrate, the photodetector configured to detect light emittedfrom the illumination source and to provide a signal in responsethereto; an optical baffle disposed between the illumination source andthe photodetector, the optical baffle configured to at leastsubstantially prevent optical crosstalk between the illumination sourceand the photodetector; a lens configured to be disposed proximate to adisplay screen, the lens configured to focus light incident upon thelens and to pass the focused light to the photodetector; and a lenssupport structure disposed over the surface of the substrate, the lenssupport structure including a first support potion and a second supportportion, the first and the second support portions configured to holdthe lens over the photodetector.
 18. The light sensing device as recitedin claim 17, wherein the display screen is a scratch-resistance glassmaterial.
 19. The light sensing device as recited in claim 17, whereinthe photodetector comprises a quad segmented photodetector.
 20. Thelight sensing device as recited in claim 17, wherein the photodetectoris configured to generate an un-lock signal.